1. Field of the Invention
The present invention relates generally to a single integrated circuit for an optical mouse, and more particularly to a single integrated circuit for an optical mouse, in which an image sensor, an analog-to-digital converter, a digital signal processor for processing digital data output from the converter, a personal computer interface and so on are integrated, thereby automatically selecting one of a universal serial bus and a IBM personal system/2, which are the personal computer interface types, in a hardware manner.
2. Description of the Prior Art
Recently, integrated circuits for an optical mouse include two integrated circuits. FIG. 1 is a block diagram of conventional integrated circuits for an optical mouse. Referring to FIG. 1, a first integrated circuit includes an image pixel array 2 that recognizes the light and shadow of a surface under an optical mouse by reacting according to the amounts of light-reflected by the surface, an Analog-to-Digital Converter (ADC) that receives an analog signal from the image pixel array 2 and converts analog data of the image pixels of the image pixel array 2 into digital data, a motion vector unit that converts the digital data output from the analog-to-digital converter and calculates motion vectors using correlations between frame data, and a quadrature generator that generates and outputs interface format signals XA, XB, YA and YB for moving distances of the motion vector unit.
A second integrated circuit 10 includes a general-purpose Main Control Unit (MCU) and a software program for MCU operation. The two integrated circuits 1 and 10 are connected to each other through the interface format signals XA, XB, YA and YB, which are rectangular signals, so the motion data of the optical mouse are transferred from the first integrated circuit to the second integrated circuit. In this case, the motion data of the X axis direction is transmitted by the interface format signals XA and XB, and the motion data of the Y axis direction is transmitted by the interface format signals YA and YB. Further, during the manufacture of the optical mouse, it is necessary to perform a process of embedding the software program in the second integrated circuit 10. Additionally, a module for interpreting the interface format signals XA, XB, YA and YB signals is needed in the software program.
The second integrated circuit 10 includes a Universal Serial Bus (USB) Serial Interface Engine (SIE), a PORT0 and a PORT1, a timer, a clock oscillator, a Read Only Memory (ROM) and a Random Access Memory (RAM). The USB SIE generates signals required for USB interfacing. The PORT0 and the PORT1 are ports whose functions can be defined by the software program since the common MCU is used. The timer allows the software program to check a predetermined time. The clock oscillator is connected to an outside crystal and generates a master clock using the crystal. The ROM and the RAM store the software program and necessary data.
An interface between the optical mouse and a Personal Computer (PC) are designed to correspond to a USB or IBM Personal System/2 (PS/2) type in a software manner. The two integrated circuits are applied to the optical mouse.
As described above, in the optical mouse to which the two integrated circuits are applied, the second integrated circuit are designed to select one of a USB interface and a PS/2 interface in a software manner to interface with the PC.
Accordingly, the conventional integrated circuits for the optical mouse are problematic in that it is essential to perform a process of embedding the software program in the second integrated circuit during the manufacture of the optical mouse and the manufacturing cost of the optical mouse is therefore increased. Additionally, the conventional integrated circuits for the optical mouse are problematic in that the two integrated circuits are used and the pattern of a Printed Circuit Board (PCB) is complicated. Additionally, the conventional integrated circuits for the optical mouse are problematic in that the two integrated circuits of the optical mouse are appropriately interfaced with each other, and the two integrated circuits are consumed because the two integrated circuits are required in manufacturing the optical mouse.